Green, ethical, energy issues in the news

70sbudgie

A lot of the submarine interconnectors are HVDC, particularly the longer ones.
www.gridwatch.co.uk has neat summaries of the UK interconnectors, but doesn't say whether the Norway one is HVDC.

I also read and thought I'd saved a very interesting webpage about current and future EU interconnectors - including one to Germany. But can't find the page now.

I believe we will start to see more DC as it is more efficient. I read something about high end domestic operating off DC circuits, with the conversion from AC as it enters the property.

I believe the early electricity networks were DC and had always understood that the switch to AC was made with the connectivity of the National Grid and the transmission network, because it is much easier to transform between voltages (which helps improve efficiencies over different distances).

However, that is a really interesting point about traditional power stations. The physics of rotating generators (combustion) is AC generation.

Martyn1981

michaels said:

Coastalwatch said:

I don't know michaels, it would certainly seem to make sense. Could it be to do with renewables generating DC while traditional power stations, which the grid was set up to service, generates in AC?

What do we use for the long subsea cables like the Norway link or even the proposed North Africa link?

Those are HVDC. Probably worth a Google if you're interested, but I think the sweet spot for efficiency is around 400-500miles. So below that AC might be preferable, but above that DC is better, with losses of around 2-3% per 1,000km.

Martyn1981

70sbudgie said:

A lot of the submarine interconnectors are HVDC, particularly the longer ones.
www.gridwatch.co.uk has neat summaries of the UK interconnectors, but doesn't say whether the Norway one is HVDC.

I also read and thought I'd saved a very interesting webpage about current and future EU interconnectors - including one to Germany. But can't find the page now.

I believe we will start to see more DC as it is more efficient. I read something about high end domestic operating off DC circuits, with the conversion from AC as it enters the property.

I believe the early electricity networks were DC and had always understood that the switch to AC was made with the connectivity of the National Grid and the transmission network, because it is much easier to transform between voltages (which helps improve efficiencies over different distances).

However, that is a really interesting point about traditional power stations. The physics of rotating generators (combustion) is AC generation.

This is my goto link for interconnectors:

OFGEM - Interconnectors

Scroll down to the table of current and planned interconnectors - It still blows my mind as we've gone from about 4GW a few years ago, to 7.4GW this year, and now another 1GW since May, and 15.9GW target by 2025. So a roughly fourfold increase in the first half of this decade. For context we average about 38GW of demand in the UK, perhaps 100GW as we head towards an all electric future/2050?

michaels

70sbudgie said:

A lot of the submarine interconnectors are HVDC, particularly the longer ones.
www.gridwatch.co.uk has neat summaries of the UK interconnectors, but doesn't say whether the Norway one is HVDC.

I also read and thought I'd saved a very interesting webpage about current and future EU interconnectors - including one to Germany. But can't find the page now.

I believe we will start to see more DC as it is more efficient. I read something about high end domestic operating off DC circuits, with the conversion from AC as it enters the property.

I believe the early electricity networks were DC and had always understood that the switch to AC was made with the connectivity of the National Grid and the transmission network, because it is much easier to transform between voltages (which helps improve efficiencies over different distances).

However, that is a really interesting point about traditional power stations. The physics of rotating generators (combustion) is AC generation.

Yes, I found domestic DC when I google for HVDC - suggestion was it makes sense with a battery/solar set up, I suspect more in areas where that might provide the majority of demand.  Not sure what is available in terms of appliances.  It would be a pain if you could only choose specialised versions (likely expensive) of everything.

Martyn1981

michaels said:

70sbudgie said:

A lot of the submarine interconnectors are HVDC, particularly the longer ones.
www.gridwatch.co.uk has neat summaries of the UK interconnectors, but doesn't say whether the Norway one is HVDC.

I also read and thought I'd saved a very interesting webpage about current and future EU interconnectors - including one to Germany. But can't find the page now.

I believe we will start to see more DC as it is more efficient. I read something about high end domestic operating off DC circuits, with the conversion from AC as it enters the property.

I believe the early electricity networks were DC and had always understood that the switch to AC was made with the connectivity of the National Grid and the transmission network, because it is much easier to transform between voltages (which helps improve efficiencies over different distances).

However, that is a really interesting point about traditional power stations. The physics of rotating generators (combustion) is AC generation.

Yes, I found domestic DC when I google for HVDC - suggestion was it makes sense with a battery/solar set up, I suspect more in areas where that might provide the majority of demand.  Not sure what is available in terms of appliances.  It would be a pain if you could only choose specialised versions (likely expensive) of everything.

That's reminded me, you might find this video interesting. I meant to post it and forgot. It's about a super efficient hotel, aiming to run everything off solar and batteries. I got a bit lost on the DC side stuff, but it uses clever computers and catcom (or something?) cables to, for instance, power all the lights, so they are DC, avoiding the losses of converting back and for.

I say it's worth a watch, as it talks about writing a new book, for a more efficient hotel, which means that others can now use it as a simple blueprint for copy and paste builds, as that's how many hotels (and other copy and paste type structures) are built.

How Big Can You Make a Passive House?

thevilla

The odd thing is that many or even most domestic appliances work on DC. Basically anything with a power block like a TV, PC etc.  LED bulbs convert to DC internally.  If we were starting again we'd probably have 12v DC as well as 240v AC ring mains.  The vagaries of international grid supply make a standard 12v DC approach easier to design for.

(Add "I believe" to all the above).

paul991

there is a company that converts your lighting circuits  to dc to run straight off a battery bank but to convert the whole country would be too big a  job

zeupater

Coastalwatch said:

I don't know michaels, it would certainly seem to make sense. Could it be to do with renewables generating DC while traditional power stations, which the grid was set up to service, generates in AC?

Hi

The issue with the US is that it's not a single grid operated at a synchronised frequency .... from previous discussions & memory, there's something like a dozen major generation areas (probably a number of very local setups too) that target operation at nominal voltage & frequency, with AC-DC-AC conversion operating at regional boundaries to eliminate differences .... this is effectively the same as operated on the short interconnections (~40miles) between the UK & France, the distance is probably currently irrelevant in most cases, however it looks like the US are finally looking at improving grid resilience to accommodate the localised variability of renewables generation as they phase out current fossil based plant.  

HTH - Z

gefnew

Here is some nice news with regards storage and batteries.
Cottingham: Europe's biggest battery storage system switched on - BBC News

Martyn1981

Might be of interest to some. This Youtube news article was recently posted on the 'Everything Electric Show' channel a spin off, of the Fully Charged show.

It's about a visit to a large home building estate (225 homes) in 2020. Nothing seismic, but still a nice watch. No gas, 170m deep boreholes for GSHP, PV, a small battery, and of course well built for high energy efficiency. In the vid they suggest (at the time) an additional £15k-£20k in capital cost, but of course annual energy and financial savings.

Also interesting that the properties are 3phase. It's stressed several times in the vid that this is to allow faster home charging for BEV's (upto 22kW). But it also occurs to me that as the properties have PV, and many are 7kWp+, then perhaps this also allows for better management by the DNO.

Is This What You Want From Housebuilders?